Effects of varying fertilization rates on morphological and mechanical characteristics of rice MR263 grown on rice husk ash (RHA) engineered alluvial soils

Abstract

This study was conducted to evaluate the effects of different rates of RHA inclusion in soil and varying fertilizer rates on morphological, yield and mechanical characteristics of MR263 rice variety. A completely randomized design pots experiment was conducted in a greenhouse involving 8 treatments in triplicates. Each pot was filled with air dried loamy sand soil mixed well with 0%,10%, 20% & 30% v/v ratios of rice husk ash (RHA), applied with 200kg/ha basal NPK fertilizer and flooded about 3-5cm above soil surface, and maintained throughout the experiment. Three 14-day old rice seedlings of uniformed size were transplanted in each pot. All experimental pots were equally split and applied with 200kg/ha and 300 kg/ha urea (46 % N), respectively on four split applications of 25% each at 15 days after transplant (DAT), 35 DAT, 55 DAT, and 75 DAT. The plant height and numbers of tillers were measured and counted on the weekly basis.The yield components such as panicle length, flag leaf length, filled grain and harvest indext were measured after harvest. The three-point bending was performed on the third internode from panicle to determine the breaking force, performed on three main tillers of each pot. The 20% RHA applied with 300kg/ha urea showed significant greater plant height(86.2cm), panicle length (28.9cm), the flag leaf length (31.8cm), as well as harvest index of 0.32. The 30% RHA applied with 200 kg/ha urea recorded the greatest internode breaking load of 2.7 kN.The X-ray Fluorescence Spectrometry (XRF) test indicated that rice plants in 30% RHA treatment having 28.5% silica content, the highest amount of all experimental treatments. This study concluded that the 20% RHA with 300kg/ha urea application rate was the optimum treatment for morphological, yield, and mechanical characteristics of MR263. Similar studies on other rice varieties are highly recommended for future studies.